Then it is odd that most every AC130 gunship and variant video which uses machine guns makes the same sound (dut-dut-dut-dut). There are a few that have the “ripping, tearing sounds” ... from below: these must have been the AC-130U variants.
here’s various quotes: “AC-130U incorporated a 25mm gun to compliment the standard 40mm cannon and 105mm howitzer.”
“The AC-130H Spectre was armed with two 20 mm M61 Vulcan cannons, one Bofors 40mm autocannon, and one 105 mm M102 cannon; after 1994 the 20 mm cannons were removed for most missions. The upgraded AC-130U “Spooky” has a single 25 mm GAU-12 Equalizer (Gattling-type) in place of the Spectre’s twin 20 mm cannons, an improved fire control system, and increased ammunition capacity. New AC-130Js based on the MC-130J Combat Shadow II special operations tanker were planned as of 2012. The AC-130W is armed with one 30 mm Bushmaster cannon, AGM-176 Griffin missiles, and GBU-39 Small Diameter Bombs.”
From this it would seem there have been various types of machine guns installed over the years and models, but only the AC-130U type seems to be fitted with a Gatling-type gun (removed, as too inaccurate from flying height and replaced with a Bushmaster variant).
So the video link was to an AC-130 firing, just not the older “U” version which had Gatling-type guns.The video likely was the AC-130W variant with the AGM-176 Griffin, Block III missiles, not Hellfires.
Most ‘AC-130’ videos on YouTube *are* actually from various helicopter gunships. The AC-130 carries literally thousands of rounds for the 40mm and under weapons so they can sit up there a long time without running out of ammo - at one point the aircraft is out of ammo and then somehow doesn’t have anything but missiles left to engage with - an AC-130 would likely still have ammo for other weapons on board and would switch to the 40mm or the 105.
But the easiest way to tell it’s not an AC-130 is the fact that it actually engaged targets that were not on the left side of the aircraft. The AC-130’s guns are all mounted on the port or left side of the aircraft and can only engage to the left. Targets to the front, rear or right side cannot be engaged by the guns of an AC-130.